Some people can't be serious. Fear of everything?

Panphobia, also known as omniphobia or pantophobia, is the fear of everything or a vague and persistent dread of some unknown evil.

So then, do all these people just commit suicide eventually? How do they go about their day-to-day lives?

Sure, all kinds of unexpected rare bad things can happen to people, but they are rare enough that they shouldn't affect you in any way. Since 9/11, did everyone in the world stop flying? Or did everyone stop working in tall high-rise buildings? No. People get into severe car accidents everyday, but does that stop people from ever driving cars again? No. The Virginia Tech massacre happened, but did that stop people from going to college? No.

It isn't worth it to live your life in fear all the time. Be concerned about more important and urgent things, like paying your bills.